Add 0.21.1 release note for submariner-io/submariner/pull/3669

Signed-off-by: Tom Pantelis <tompantelis@gmail.com>

Author: tpantelis

src/content/community/releases/_index.en.md

@@ -9,6 +9,7 @@ weight = 40
 
 * The cluster service CIDRs are now correctly discovered on Kubernetes 1.33+ in managed Kubernetes environments like EKS and GKE.
 * Calico’s default IPPool encapsulation is enforced as IPIP on IBM ROKS, even when controlled via Tigera Installation CR.
+* Fixed an issue which resulted in a stale `RouteAgent` resource when the associated pod was terminated or the node was powered off.
 
 ## v0.21.0